This invention relates generally to over-center draw latches for use in securing two closure members together. More specifically, the present invention relates to over-center draw latches of the flexible or elastic type.
Many types of over-center draw latches are generally known in the art. One such type of over-center draw latch is taught in my U.S. Pat. Nos. 3,181,095, issued May 4, 1965; 3,466,076, issued Sept. 9, 1969. The latches disclosed in these patents essentially comprise a keeper and a one-piece part having three segments: a base segment, a locking segment, and an intermediate segment wherein the intermediate segment is flexibly connected to the base and locking segments. When in a latched condition, the locking segment is detachably connected to the keeper and is in overlying relation to the keeper, the base segment, and the intermediate segment.
Another known over-center draw latch is disclosed in U.S. Pat. No. 4,540,206, issued Sept. 10, 1985, which comprises a keeper, a mounting bracket, an adjustable lever connected to the mounting bracket, and a locking member connected to the adjustable lever. The adjustable latch, which is made entirely of molded plastic resin, incorporates an adjustability feature to compensate for variations in the closure members in manufacturing or due to deformation during use.
These latches were often considered desirable because they provided positive over-center latching, were lightweight and also were inexpensive to manufacture. Furthermore, these latches were attractive in appearance. Typically, however, these latches were of a molded plastic construction and were incapable of use in situations where high loads were placed on the latch. Another disadvantage in these latches was the fact that considerable precision was required in the installation of the latch and the keeper in order for the latch to operate properly.
Flexible draw latches are also known in the art and have been used for many years. Perhaps the simplest example of a flexible draw latch comprises a mounting bracket, a rubber stretch arm affixed to the bracket, and a keeper. These flexible draw latches are typically used to secure loose fitting hoods or covers on heavy machinery or mechanical equipment. In operation, the rubber stretch arm would be pulled up and into engagement with the keeper, whereby the elasticity of the rubber arm would keep the hood or cover secure. Although these latches were not very pleasing in appearance and did not provide the more positive over-center latching action, they were considered desirable because the flexibility of the rubber arm compensated for misalignment of the bracket and keeper during installation. The flexibility of these latches also permitted the closure members to move relative to one another without causing the latch to release and thus were considered desirable for use in situations where vibrations of the panels was to occur. Moreover, the relative movement of the closure members in all directions would cause the displacement and misalignment of the keeper and mounting bracket during use, even if they were properly aligned in installation. The flexibility of the latch, unlike the plastic draw latches, permitted the latch to compensate for these misalignments without releasing. Another advantage of these flexible draw latches was that the load capability of the latch could be varied, within a range, by simply increasing or decreasing the distance between the bracket and the keeper and, thus, the tension on the rubber stretch arm. In high load situations, this type of latch became impractical, however, because of the difficulty in stretching the heavy-duty rubber arm required in such situations.
Another type of flexible draw latch is also known which was primarily developed to overcome the disadvantages of the above-mentioned flexible latch by providing a lever handle to assist in stretching the rubber arm. Essentially, these lever-assisted flexible draw latches comprise a bracket, a rubber stretch arm, a lever handle and a keeper. The rubber stretch arm is connected at one end to the bracket and connected at the other end to the lever at a point intermediate the ends of the lever. To operate the latch, the lever handle was inserted in the keeper and pivoted to stretch the rubber arm and then seating to secure the latch with a positive over-center action. Despite its advantages over the previous flexible draw latches, however, these lever assisted latches were considered unsightly and their use was essentially limited to high load situations where heavy-duty latches are required.
I have invented a simple draw-pull latch for use in securing two closure members together which provides the advantages of a flexible locking member in an aesthetically pleasing latch which is inexpensive to manufacture, easy to use, and has a wide variety of practical applications.